1. Field of the Invention
This invention relates to a device for generating vibration that is mainly mounted in a portable apparatus (including such electronic devices as a mobile phone, a PHS, a small wireless communications device, and other various portable information communications terminals) to perform a soundless alarm function, specifically to a holding structure of a circuit board in a housing of a portable communication device and the device for generation vibration mounted on the circuit board, and a fixing holder to position the fixing point of the device for generation vibration.
2. Description of Related Art
A sudden incoming ring tone of a portable apparatus may sometimes disturb others in, for example, a quiet public space such as an art gallery and a concert hall with many people in a room for important commercial negotiations or conferences. Therefore, a wireless alarm function using a device for generating vibration to report an incoming signal with sensible vibration (generally called “manner mode”) is mounted in various portable apparatuses.
The devices for generating vibration can mainly be classified into two types from the viewpoint of structures. One of these is a so-called motor for generating vibration using a cylindrical or flat type small motor (hereafter briefly referred to as a vibration motor, as required), and the other is a so-called multi-functional device equipped with both sound and buzzer functions of a speaker drive type in which a magnetic circuit section is reciprocated by low frequency signals (or a vibration linear device specialized for vibration function hereafter collectively referred to as a vibration actuator, briefly, as required).
In the case of the aforementioned vibration motor, a portable apparatus such as a mobile phone is vibrated by providing a rotating shaft driven by the motor with a weight having an eccentric center of gravity or with a deflecting member to utilize an unequal load due to centrifugal force caused by eccentric rotation of the weight etc. having an eccentric center of gravity during rotor operation. As such various portable apparatuses are used more popularly, the percentage of apparatuses equipped with such mechanism and frequency of using such mechanism are increasing day by day.
Similarly, the aforementioned vibration actuator equipped with both the vibration generating function of the magnetic circuit section by low frequency signals and the sounding function within a human voice range can be replacing the existing speaker and can realize highly efficient use of installation space because of adoption of a flat type multifunctional integral part and is more widely used corresponding to each application. Especially recent mobile phones and PHSs, which have become popular and of which the size is greatly reduced, are efficiently equipped with these two types of devices for generating vibration in their limited mounting spaces in the housings.
In the housings of these portable apparatuses, a power supply method from a power source (mainly circuit board) to a main unit of a device for generating vibration and its holding structure is improved day by day. For example, instead of a conventional connecting method such as using a soldered lead wire or a connector, a structure having a combination of an elastic pressing body and a leaf spring-like power supply terminal or a structure having a power supply terminal directly connected to a circuit board by soldering are newly examined.
For instance, a power supply terminal structure shown in FIGS. 7 and 8 is conventionally used as a method in which the aforementioned vibration motor can be built into a housing of a main unit of a portable communication apparatus (hereafter briefly referred to as an apparatus main unit, as required) in relatively few man-hours for assembly and which enables a direct power supply from a circuit board to a motor main unit.
Power supply terminals 104 shown in FIG. 7 are arranged on a terminal block 110 on which an end of a housing case 103 of a vibration motor 101 having a weight 106 is to be mounted and comprises leaf springs, one end of each of which is soldered to the terminal at a connecting portion 104e and in which a part of each strip plate extending from the aforementioned terminal block 110 to a contact portion 104d is bent at a bending portion 104f. 
The contact portion 104d at a forward end of a movable portion of the power supply terminal 104 is pressed onto a power supply land 55 of a circuit board 50 provided in the apparatus main unit housing 200 by allowing the power supply terminal 104 to be elastically deformed at this bending portion 104f as shown in FIG. 8. In addition, there is a method in which an elastic spring body 130g is arranged between the power supply terminal 104 and a housing case 103 as a part of a holder 130 covering the aforementioned housing case 103 and is combined with a housing of the apparatus main unit housing 200 to press the contact portion 104d of the power supply terminal 104 onto the power supply land 55 utilizing the interaction between the rubber elasticity of a convex section of the aforementioned elastic pressing body 130g and leaf spring elasticity of the aforementioned power supply terminal 104 as shown in FIG. 8 (b) (for example, see patent references 1 through 3).
Patent reference 1: JP 2000-78790A
Patent reference 2: WO99/23801A
Patent reference 3: JP 2001-95200A
Since the vibration motor 102, for example, shown in FIG. 8 according to the Patent Reference stated above is mounted on a plate of a circuit board 50 with a power supply terminal 104 inserted between an elastic pressing body 130g of a holder 130 for holding the vibration motor 102, there is a problem that an excessively large space is occupied in a direction of the height inside a housing of a portable apparatus 200, leading to dissatisfaction of a development criterion that requires a compact mobile communications device.
In fact, the minimum outside diameter of a current cylindrical vibration motor is 4 mm, while a total height of the vibration motor with the elastic holder 130 in between is approximately 5 mm, which is extremely large compared to other electronic parts mounted on a circuit board. In particular, with the demand for a reduction in the size and height of a mobile communications device represented by a mobile phone, the problem to overcome was an arrangement of a device for generating vibration for the vibration motor enabling a compact mobile device. Moreover, there were many problems in a mounting method of the vibration motor 102 such that it is difficult to obtain a sufficient level of vibration for a user because a diameter of an eccentric weight 106 was decreased along with a decrease in a diameter of the vibration motor 102.